The aim of this Phase I project is to develop novel spectroscopic probes for applications in cell biology. Specifically, it involves the synthesis and evaluation of new types of "hybrid" molecular probes, combining both a nitroxide free radical center and a fluorescent moiety in one molecule. These proposed dual-feature molecular probes will serve as reporter molecules, producing measurements of molecular motion, microviscosity, temperature, cell-surface potentials, membrane fluid and through- membrane transport. Two classes of novel probes are proposed a) Redox and free radical probes and b) Micro viscosity Probes. Test compounds will be synthesized and evaluated for their fluorescence and sensitivity. In Phase II, applications of these novel probes in molecular and cell-biology will he studied and fiber optic detection devices based on these molecules will be built in collaboration with Southwest Research Institute. PROPOSED COMMERCIAL APPLICATIONS: There is a considerable commercial potential for the new combined nitroxide-fluorescent probes in biological research and medical diagnostics. There is also commercial potential for devices capable of rapid detection for medical diagnosis and commercial uses.